Longer-term follow-up and outcome by tumour cell proliferation rate (Ki-67) in patients with relapsed/refractory mantle cell lymphoma treated with lenalidomide on MCL-001(EMERGE) pivotal trial.

Patients with mantle cell lymphoma (MCL) generally respond to first-line immunochemotherapy, but often show chemoresistance upon subsequent relapses, with poor outcome. Several studies of the immunomodulator, lenalidomide, have demonstrated its activity in MCL including the MCL-001 study in relapsed/refractory patients who had failed defined prior therapies of anthracyclines or mitoxantrone, cyclophosphamide, rituximab and also bortezomib. We present here the long-term efficacy follow-up of the prospective phase II MCL-001 study (N = 134), including new exploratory analyses with baseline Ki-67 (MIB1), a biological marker of tumour proliferation. With longer follow-up, lenalidomide showed a 28% overall response rate [ORR; 8% complete response (CR)/CR unconfirmed (CRu)]. Median duration of response (DOR), progression-free survival and overall survival were 16·6, 4·0 and 20·9 months, respectively. Myelosuppression continued to be the most common grade 3/4 toxicity. Several studies of MCL patients treated with chemotherapy, rituximab and bortezomib have shown an inverse association between survival and Ki-67. Ki-67 data in 81/134 MCL-001 patients showed similar ORRs in both low (<30% or <50%) versus high (≥30% or ≥50%) Ki-67-expressing groups, yet lower Ki-67 levels demonstrated superior CR/CRu, DOR and survival outcomes. Overall, lenalidomide showed durable efficacy with a consistent safety profile in heavily pretreated, relapsed/refractory MCL post-bortezomib.

Single-agent lenalidomide in patients with mantle-cell lymphoma who relapsed or progressed after or were refractory to bortezomib: phase II MCL-001 (EMERGE) study.

PURPOSE: Although dose-intensive strategies or high-dose therapy induction followed by autologous stem-cell transplantation have improved the outcome for patients with mantle-cell lymphoma (MCL), most eventually relapse and subsequently respond poorly to additional therapy. Bortezomib (in the United States) and temsirolimus (in Europe) are currently the only two treatments approved for relapsed disease. Lenalidomide is an immunomodulatory agent with proven tumoricidal and antiproliferative activity in MCL. The MCL-001 (EMERGE) trial is a global, multicenter phase II study examining the safety and efficacy of lenalidomide in patients who had relapsed or were refractory to bortezomib. PATIENTS AND METHODS: Lenalidomide 25 mg orally was administered on days 1 through 21 every 28 days until disease progression or intolerance. Primary end points were overall response rate (ORR) and duration of response (DOR); secondary end points included complete response (CR) rate, progression-free survival (PFS), overall survival (OS), and safety. RESULTS: In all, 134 patients were enrolled with a median age of 67 years and a median of four prior therapies (range, two to 10 prior therapies). The ORR was 28% (7.5% CR/CR unconfirmed) with rapid time to response (median, 2.2 months) and a median DOR of 16.6 months (95% CI, 7.7 to 26.7 months). Median PFS was 4.0 months (95% CI, 3.6 to 5.6 months), and median OS was 19.0 months (95% CI, 12.5 to 23.9 months). The most common grade 3 to 4 adverse events were neutropenia (43%), thrombocytopenia (28%), anemia (11%), pneumonia (8%), and fatigue (7%). CONCLUSION: The MCL-001 study demonstrated durable efficacy of lenalidomide with a predictable safety profile in heavily pretreated patients with MCL who had all relapsed or progressed after or were refractory to bortezomib.